1. Field of the Invention
The invention relates to a device for metering bulk material, in particular plastics granulate, for machines processing plastics granulate, in particular for injection molding machines, wherein at least one material funnel into which bulk material can be filled and which has a material valve is provided and a weighing container connected to weighing scales is optionally arranged below the material valve, wherein a control unit is provided for the weighing scales and material valve.
2. Discussion of Background Information
A device of this type is known from U.S. Pat. No. 3,822,866 A, wherein a method for the provision of bulk material before metering is also described. The plastics granulate is provided by the delivery device in containers before metering.
A device for delivery and metering of bulk material is also known from DE 195 28 636 A1, wherein the metering device simultaneously serves as delivery device.
Furthermore, a device for delivery comprising multiple containers is known from US 2008/049546 A1.
In addition, a method and a gravimetric mixer for delivering measured quantities of granular materials and colorants, in particular pigments in liquid form, is known from DE 696 27 717 T2.
Furthermore, a gravimetric blender and hopper with integrated discharge valve for granular material is known from DE 05 075 472 T1.
Furthermore, a gravimetric mixer comprising a frame, a removable material storage funnel with a valve, a weighing container with weight detection and a mixing chamber below the weighing container is known from DE 697 32 659 T2.
As shown above, different amounts of different plastics granulate are introduced in batches according to freely adjustable formulations and each type of plastics granulate, such as for example new material, main batch, additives and/or material to be ground, is passed through a material funnel successively or also in parallel to a weighing container or mixing container, depending on the system, via a material valve.
In most cases, a formulation is used that includes the individual types of plastics granulate, such as for example new material, material to be ground, main batch and/or additives. Thereby, new material and material to be ground are in a weight-related disproportion to the main batch and additive. Thus, the proportions of new material and material to be ground can make up for approximately 70% and 30%, and main batch and/or additive amount to 1 to 2% in relation to the new material. A separate container is provided for each type of plastics granulate.
In order to be able to fulfill the standards above, material valves are required at the bottom end of the material funnels.